Fort Worth daily gazette. (Fort Worth, Tex.) 1882-1891, 1887-07-30
ABOUT THERMOMETERS.
TIE instruments 30 which All Rush III
Hot Weaiher-chs gubrs Free
qGsntiy Imperfect.
Record Of g Creep Tnc.m"mefsr-tfoyg
They ara n1ade-The CsUtisr4ae- U.c
OF lho Spirit Lhsrm9 I1l@lsr.
Ncw York liail aud ENprcs=


Daring tce hot spell there il no inst7u-
meng that IS studied more carefully tha1
the Thermometer. Every one VANS to
know how hot /. IS esc1 day, and all con
tinualy consul. those little glass tubes.
These vary sometimes several degrees 8
the same instsly. SAD dealer in Their
mometsrs to = reporter:
"rhermone,lrs are very curious IN
struments. Sometimes We hld oGe thai
Is al right at cer,4jn points, and t Others
it VIII be Sc RAJ degrees out OF the way.
These variations are c2used BY irregularI-
ties in tn tue. TIE tu5es are verq fye-
qlently imperfect. When the tube
IS too lsrge of course the regis
traii0n IS several degrees Lower t1an
1t should be. Sometimes the tube is too
small, 8Id then the mercury shoots up
higher than it u2it to- The tubes have
10 be seasoned. Tajs takes several
months. When glass is new it changes :,
expands, COLtract5 sid warns sInost as
badly IS green wood Very often, after
buying 2 cheapthermOmete the customer
has brought it bsck and said it registered
loo in the shade, when the temperature
vas only ninety. The best therm0mtt tiers
are made in London Thee imported
Thermometers are, however, very tN)en-
siye. Some very good ones are inside i'd
this country at NeT Lebanon, y Y, SIC
2. Rochester -
HOW THEY ARE MADE.
Glow are tdeg made VA asked.
"IHe tuDe is blown TO the size wanted
The top being left open. The bu.b Is laei
ac2t,d to exDel The air. and Wai.c htatc,
the open euj is Inserted into some mer
curry. AS the tabe c00ls the me-cuc-
runs into The vacuum. The open end il
tlen sealed end ina tube placed on
scale. Then it is placed IN water Of
known temperature sud the point L
which the mercury rises is marked. sly
erai tests like this Sre made before m
instrument is offered for sale"
GLOW are the thermometers proved It
9e sccurate7"
"THere IS q place g Harvard college
for testing them. They ere carefully *
Gmiped 81 different temperatures, ana
snY y&riaCiO1 Is marked. A certificate j
given win every instrument tha5 Is TX.
amiaed."
(Which scsla do you thing is t..
best:"
The cent;crada is the one tli7I
should he generally adopted Foe Ia,
use Of brewers there j. thermomete
about three feet long, wish G bulb a5ou
two feet in length. The scale Of THIS i
short, and is only marked for few de
grees above freezing point Auot1e
odd Instrument is Of English make
and c2D be read in IN.
dark. The tube IS filled with
green composition and contains phos
p1orus. Spirit thermometers are use,
1Jr very cc!d climates, IS mercury COZ
geals at 80 below zero. These Canno
be used TO measure extreme heat, =
above certain temperature the Ilqli,
expands too fast; it bJus st lGJ go
very high temperatures the pyrcmete
takes the place of the thermometer. IN
heat is measured by the expansion O
metals, and Will accurately register III
10 700 Fe5rile Thermometers, for tn
use Of physicians, ale very carefully made
and q certificate Is sold with them inGi
Gazing their variations from perftc. &C
cur&cy"